Unicode 输入法

What is a Unicode Input Method?

A Unicode input method is any technique, tool, or system that allows a user to enter a Unicode character that is not directly accessible from their physical keyboard. Because Unicode defines 154,998 characters across 168 scripts while keyboards typically have 100–120 keys, the gap between "characters you can type" and "characters that exist" is enormous. Unicode input methods bridge that gap.

The major categories of Unicode input methods are: IME (Input Method Editor), dead keys, Compose key sequences, OS character pickers, hex code entry, copy-paste from reference tools, and entity codes in markup languages.

The Landscape of Unicode Input Methods

Choosing the Right Method

For diacritics (accented Latin): Use your keyboard layout's dead keys (European keyboards) or Option key combos (macOS). These are optimized for exactly this purpose and require minimal setup.

For CJK characters: Use a dedicated IME. There is no shortcut — Japanese, Chinese, and Korean input requires a proper phonetic or structural IME.

For occasional symbols (copyright, trademark, arrows, mathematical): Use the OS character picker (Win+. on Windows, Ctrl+Cmd+Space on macOS) or memorize a handful of keyboard shortcuts for your most-used characters.

For technical/programming work: Learn hex input methods. Being able to type U+2014 and convert it to — is faster than reaching for a mouse.

For web/HTML development: Use named HTML entities (—, …,  ) for clarity, or numeric hex entities (—) for any character.

HTML and CSS Entity Methods

<!-- Named entities (most readable) -->
&mdash;    <!-- — em dash -->
&ndash;    <!-- – en dash -->
&hellip;   <!-- … ellipsis -->
&nbsp;     <!-- non-breaking space -->
&copy;     <!-- © copyright -->
&reg;      <!-- ® registered -->
&trade;    <!-- ™ trademark -->

<!-- Decimal numeric entities -->
&#8212;    <!-- — em dash -->
&#8230;    <!-- … ellipsis -->

<!-- Hexadecimal numeric entities (preferred in modern HTML) -->
&#x2014;   <!-- — em dash -->
&#x2026;   <!-- … ellipsis -->
&#x1F600;  <!-- 😀 emoji -->

/* CSS unicode escapes */
.icon::before {
  content: "\2022";   /* • bullet */
  content: "\2192";   /* → right arrow */
  content: "\1F600";  /* 😀 emoji */
}

Cross-Platform Summary

macOS:
  Option + E, then E = é (dead key)
  Ctrl + Cmd + Space = Character Viewer (picker)
  Option + - = – (en dash)
  Shift + Option + - = — (em dash)

Windows:
  Alt + 0169 = © (alt code)
  Win + . = Emoji & Symbols (picker)
  2014 then Alt+X = — (hex input, Word only)

Linux:
  Compose + e + ' = é
  Ctrl+Shift+U then 2026 Enter = … (GTK hex input)
  IBus/Fcitx for CJK

Quick Facts